In recent years, in association with progress in the fields of computer-related technology and man-machine interface or with improvement in network environment, more and more documents have been electronized, and also in association with the technological progress, the tendency for paper-less environment in business offices has been promoted.
To describe the situation more concretely, various types of document are prepared (electronized) on a screen of a personal computer/work station, and such operations as editing, copying, transferring, sharing, filing, proofreading, and retrieving the electronized document information can easily be executed in a computer system (in a digitalized world or in a virtual reality). Especially with development of a network, now it is possible to distribute (transfer) an electronized document to each individual without outputting the document with such a device as a printer, which further promotes the tendency for paper-less environment in offices.
Also an electronized document can automatically and systematically be managed by a document information management system built in a computer, so the works for sorting stored documents or retrieving a document which a user hopes to read have become easier, and further there are provided the advantages such as reduction of a total volume of documents by sharing documents among a plurality of users, improvement in security of secret documents by setting a password or the like, and correlation of a plurality of documents to each other.
However, although electronized documents provide. various merits, when compared to a document outputted on actual recording paper (described as paper document hereinafter), there are various types of restriction in easiness to read; portability, easiness to be handled, environmental conditions for its availability, or continuity to actual work, and for this reason, when using an electronized document for an actual job, in many cases it is more efficient to output the electronized document with a printer or the like on recording paper once and then use it as a paper document. So, in the office environment in the future, paper documents and electronized documents would coexist and be used according to a purpose of each job.
With the conventional technology, however, as there is no continuity or correlation of information as digital information between the digital world such as a computer system and paper documents, there have been the problems as described below.
At first, even when electronized documents are put under management by a document information management system built in the digital world, once an electronized document is outputted as a paper document, the correlated information which the electronized document has, such as address information, security information such as a password, and linkage information for linking the document to other document each in the document information management system disappear, and for this reason the paper document has only a value as output from the document information management system.
Secondly, as it is impossible to directly access the digital world using a paper document as a medium, it is required for a user to operate a keyboard or the like to access it, which means low convenience in actual use.
Although there has been a method to directly access the digital world using paper as a medium like in a case of a mark sheet, as a previously formatted and dedicated mark sheet is used, there are various restrictions in actual use, and it can not be used as a general document.
Thirdly, in the digital world, there is a hypertext document based on an advanced concept for an electronized document, but when this hypertext document is outputted as a paper document, only visualized two-dimensional information is outputted and original information as a hypertext is lost, so that there are disadvantages such as loss of information and lowering in its convenience.
Concretely, a hypertext is a group of linked (correlated) texts (electronized documents), and the basic concept is realization of multi-media software enabling the user to refer to each of texts multi-dimensionally correlated in a layered form through link structure in an arbitrary order. For this reason, the hypertext document contains, in addition to information visually provided to the user, information used for forming the link structure (namely, information as a hypertext). But once the hypertext document is outputted as a paper document, the information as the hypertext is lost, so that the outputted paper document is not any more a hypertext document.
It should be noted that, as a hypertext document can exist only as an electronized document in the conventional technology, the concept of hypertext itself has been used only in the digital world (virtual reality) in which electronized documents are treated. For this reason, there has not been a concept for realization of a hypertext by using a paper document, which is treated as a hypertext document, in the real world (this concept is defined and described as a paper hypertext hereinafter).